1. Field of the Invention
This invention relates to a tool bar for use with agricultural implements and more particularly to a tool bar including first and second tool bar sections which may pivotally move upwardly and downwardly with respect to a tongue secured to the tool bar so as to provide a flex-row averaging system.
2. Description of the Related Art
Many types of tool bars have been previously provided for supporting agricultural implements thereon such as planter units, cultivator units, etc. In some cases, the tool bar comprises an elongated tool bar member which is transversely disposed with respect to a forwardly extending tongue which is secured to the tractor. Inasmuch as the current tool bars may be very long, it has been found necessary to provide fold joints in the tool bars so that the opposite ends of the tool bar may be folded inwardly with respect to the tongue so that the implement may be transported from one field location to another field location. Further, when tool bars of considerable length are employed, it is necessary to provide some sort of hinge or joint in the tool bar to permit the opposite ends of the tool bar to move upwardly and downwardly to conform to irregular terrain over which the implement is being moved, such as when the field has terraces. For example, U.S. Pat. No. 4,504,076 discloses a forward-folding agricultural implement which allegedly enables narrow row spacing of planter units mounted on the tool bar. However, due to the fact that the implement of U.S. Pat. No. 4,504,076 includes a rearwardly extending frame member which has a wheeled carriage or truck mounted thereon behind the transversely extending tool bar, it is impossible to closely space the two innermost planter units to accommodate extremely narrow row spacing such as 15-inch rows.
U.S. Pat. No. 4,582,143 also discloses a forwardly-folding agricultural implement, but that implement also includes a rearwardly extending draw bar or frame member, positioned rearwardly of the transversely extending tool bar, which has wheels mounted at the rearward end thereof. The device of U.S. Pat. No. 4,582,143 is believed to suffer the same shortcomings as U.S. Pat. No. 4,504,076.
Thus, it is extremely important to provide a hinge arrangement at the center of the tool bar which permits the attachment of implements thereto, such as planter units, in extremely narrow row spacing such as 15-inch spacing. If a single horizontally disposed hinge pin is provided between the outer wing sections, and the planter units are secured to the tool bar closely adjacent the hinge pin, upward flexing of the wing sections could cause the seed boxes on the innermost planter units on the wing sections to come into contact with one another and damage the same, and downward flexing of the wing sections could cause the gauge wheels on the innermost planter units on the wing sections to come into contact with one another and damage the same. It is for those reasons that the instant hinge joint is disclosed for use in a tool bar which not only permits narrow row spacing of implements on the tool bar such as 15-inch spacing, but which includes means for preventing damage to the innermost planter units or implements when the wing sections of the tool bar are moved upwardly or downwardly with respect to the forwardly extending tongue of the implement.